1. Field of the Invention
The present invention relates to optical character recognition and particularly to locating blocks of indicia on pages for subsequent processing of such indicia by optical character recognition techniques. More specifically, this invention is directed to apparatus for use in the machine reading of address information on envelopes, and especially to circuitry for locating address information on a moving envelope and subsequently outputting video data corresponding to a region on the envelope which includes the address information. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
While not limited thereto in its utility, the present invention is particularly well suited for incorporation in a mail processing system to facilitate the machine reading of address information from envelopes moving on a transport system. Mail processing systems which employ optical character recognition apparatus and techniques for "reading" address information are well known in the art. Such systems are, for example, employed to enable the automatic printing on the envelopes being "read" of a bar code commensurate with the addressee's postal zip code. In the known systems, envelopes will move along a transport path through a character recognition station where an image of the address information is "captured" by a "camera" for processing by the character recognition logic.
In order to enable the processing of pieces of mail at an acceptable speed, it has previously been necessary for the OCR apparatus to know with a reasonably high degree of precision the location, i.e., the field, on the envelope of the address information to be read. Restated, if the "X" and "Y" coordinates of an edge of the field in which the address to be read is located and the size of the address block are not known, the OCR apparatus will have to process an image of the entire envelope. The processing of the image of the entire envelope is a relatively time-consuming task. Accordingly, present mail processing systems will be configured to process similar envelopes where the address block is always in the same location and the window in video memory may thus be preset during a setup procedure. Present mail processing systems, accordingly, cannot process mixed mail pieces which have different address block locations.